Usefulness of the SNR Using the Subtraction Method and Image Visibility Using the Howlett Chart Method in X-Ray Fluoroscopic System  

作　　者：Sadamitsu Nishihara Yuki Yamashita Naoki Kawai Hideki Otsuka 

机构地区：[1]Department of Radiological Technology, Tokushima University School of Health Sciences, Tokushima, Japan Department of Radiology, Kansai Electric Power Hospital, Osaka, Japan [2]Department of Radiological Technology, Tokushima University School of Health Sciences, Tokushima, Japan Department of Radiological Technology, University of Miyazaki Hospital, Miyazaki, Japan [3]Subdivision of Biomedical Information Sciences, Institute of Health Biosciences, University of Tokushima Graduate School, Tokushima, Japan

出　　处：《Open Journal of Medical Imaging》2014年第2期49-56,共8页医学影像期刊（英文）

摘　　要：X-ray fluoroscopy has been used not only for diagnoses but also for treatment, as in interventional radiology. The aim of this study is to assess the usefulness of the signal-to-noise ratio (SNR) using the subtraction method, which is used in the quality assurance/quality control (QA/QC) of magnetic resonance imaging (MRI) equipment, and image visibility using the Howlett chart method in the fluoroscopic examination. The fluoroscopy unit has a detector with an image intensifier and a color liquid crystal display. A 2620 dosimeter and an ionization chamber were selected for the dose measurement. Fluoroscopic images for visual and physical evaluations were collected as dynamic data. The skin surface absorbed dose rates for each tube current were measured using a dosimeter. The SNR using the subtraction method and image visibility using the Howlett chart method were examined. The results from both indicate that as the SNR improves, visual evaluation increases, but the rate of increase gradually saturates. Therefore, physical and visual evaluations are possible with the SNR using the subtraction method and the image visibility using the Howlett chart method.X-ray fluoroscopy has been used not only for diagnoses but also for treatment, as in interventional radiology. The aim of this study is to assess the usefulness of the signal-to-noise ratio (SNR) using the subtraction method, which is used in the quality assurance/quality control (QA/QC) of magnetic resonance imaging (MRI) equipment, and image visibility using the Howlett chart method in the fluoroscopic examination. The fluoroscopy unit has a detector with an image intensifier and a color liquid crystal display. A 2620 dosimeter and an ionization chamber were selected for the dose measurement. Fluoroscopic images for visual and physical evaluations were collected as dynamic data. The skin surface absorbed dose rates for each tube current were measured using a dosimeter. The SNR using the subtraction method and image visibility using the Howlett chart method were examined. The results from both indicate that as the SNR improves, visual evaluation increases, but the rate of increase gradually saturates. Therefore, physical and visual evaluations are possible with the SNR using the subtraction method and the image visibility using the Howlett chart method.

关 键 词：X-RAY Fluoroscopic SYSTEM SIGNAL-TO-NOISE Ratio Howlett Chart VISIBILITY 

分 类 号：R73[医药卫生—肿瘤]